1. Field
This application relates generally to wireless communication and more specifically, but not exclusively, to determining transmission parameters for very high throughput transmission.
2. Introduction
Some types of wireless communication devices employ multiple antennas to provide a higher level of performance as compared to devices that use a single antenna. For example, a wireless multiple-in-multiple-out (MIMO) system (e.g., a wireless local area network (WLAN) that supports IEEE 802.11n or 802.11ac) may use multiple transmit antennas to provide beamforming-based signal transmission. Typically, beamforming-based signals transmitted from different antennas are adjusted in phase (and optionally amplitude) such that the resulting signal power is focused toward a receiver device (e.g., an access terminal).
A wireless MIMO system may support communication for a single user at a time or for several users concurrently. Transmissions to a single user (e.g., a single receiver device) are commonly referred to as single-user MIMO (SU-MIMO), while concurrent transmissions to multiple users are commonly referred to as multi-user MIMO (MU-MIMO).
An access point (e.g., a base station) of a MIMO system employs multiple antennas for data transmission and reception, while each user employs one or more antennas. The access point communicates with the users via forward link channels and reverse link channels. In some aspects, a forward link (or downlink) channel refers to a communication channel from a transmit antenna of the access point to a receive antenna of a user, and a reverse link (or uplink) channel refers to a communication channel from a transmit antenna of a user to a receive antenna of the access point.
MIMO channels corresponding to transmissions from a set of transmit antennas to a receive antenna are referred to spatial streams since precoding (e.g., beamforming) is employed to direct the transmissions toward the receive antenna. Consequently, in some aspects each spatial stream corresponds to at least one dimension. A MIMO system thus provides improved performance (e.g., higher throughput and/or greater reliability) through the use of the additional dimensionalities provided by these spatial streams.